Swimming — slowly — beneath the chilly Arctic waters is one of the most mysterious sharks in the world: the Greenland shark. Not much is known about these rare creatures, but what we do know makes them the coolest — and oldest — sharks ever!
Greenland sharks are sometimes called sleeper sharks, not because they sleep a lot — it's because they don’t move around much. Greenland sharks are slow — they swim along at a pace of just over one kilometre an hour. On land that would be a nice stroll. So Greenland sharks won’t be winning any swimming races. Fortunately these sharks are big enough that nothing usually chases them.
Greenland sharks live in the chilly waters of the Arctic Ocean and the North Atlantic. In the winter, they’ll move closer to the coasts of places like Nunavut, Newfoundland, Greenland and Iceland, but they don’t migrate very far south. They like water temperatures between -1ºC and 10ºC.
These sharks enjoy swimming around the bottom of the ocean. They’ve been spotted as deep as 2,200 metres. It’s one of the reasons so little is known about Greenland sharks. They’re hard to find at such great depths and with so little light.
AP Photo/David Goldman
Despite being slow swimmers, Greenland sharks seem to do okay for food. They’ve been found with fish, seals, polar bears and reindeer in their stomachs. One shark was even spotted snacking on a moose! It may be that Greenland sharks use their slow, but stealthy, swimming to sneak up on prey. But these sharks are also scavengers, so it’s more likely that their prey is dead before the shark comes across it.
The chemicals in a Greenland shark’s body that lets it live in cold and deep water make it toxic to humans. But in Iceland they've found a way around this problem. The shark meat is fermented and dried for months before being eaten. It’s a dish you probably have to be Icelandic to appreciate, but visitors have been known to try it on a dare.
That makes them the longest living of all vertebrates (vertebrates are animals with backbones, not squishy ones like clams or jellyfish). Greenland sharks aren’t adults until they’re around 150 years old, and they keep growing their whole lives at a rate of one centimetre a year. So the bigger the shark, the older it is! Sharks have been studied at over five metres long, but scientists think there are even bigger ones out there.